ANCHORAGE, Alaska  Visitors to Glacier Bay National Park and Preserve were in for a treat this summer: A record number of humpback whales were sighted either in Glacier Bay or in waters just outside the stunning marine wilderness in southeast Alaska.

The 3.3-million-acre park, with its wealth of whales, snowcapped mountains, tidewater glaciers and deep fiords, is increasingly popular with humans, too. Last year, the park welcomed 413,000 park visitors, 54,000 more than the previous year.

Chief park ranger Randy Larson said more visitors were expected this year.

The popularity of the park is testing measures updated this year to keep whales away from boat traffic. The vessel management program is working well, park officials say, with no whales reported struck by boats inside the park this summer.

Humpback whales, which can grow to 50 feet long and weigh more than 35 tons, were once hunted nearly to extinction. They have been listed as endangered under the Endangered Species Act for more than three decades, and have been protected internationally since 1966.

There are now an estimated 30,000 humpback whales worldwide, with between 6,000 and 8,000 in the North Pacific, according to the National Marine Fisheries Service.

An estimated 1,000 humpbacks are in northern southeast Alaska waters, although that number is believed to be low, said University of Alaska Southeast marine biologist Jan Straley.

They gather in summers in Glacier Bay to feed on schooling fish.

The North Pacific population is growing by up to 7 percent a year, Straley said.

It was a good summer for humpbacks in and near Glacier Bay. From early June to the end of August, 161 individual humpback whales were identified by their tail flukes, including 17 females with calves -- more than in any previous year.

"It gets more and more gratifying all the time," said Chris Gabriele, a whale biologist at Glacier Bay. "We have mothers, grandmothers and great-grandmothers."

During the cruise ship season, thousands of visitors arrive each day in the park. This summer, two cruise ships were allowed in the park almost every day, increasing the number of cruise ship visits to 225, up from 206 in 2005.

The park, reachable only by plane or boat, also is popular with charter and recreational boaters. A limit of 36 vessels are allowed in the park each day.

There were no reports of boat strikes this summer, but fatal boat strikes do happen. In 2001, a 45-foot pregnant whale was found floating at the mouth of Glacier Bay. It was later determined the whale died of massive head injuries after being struck by a cruise ship.

In 2004, a young whale was found dead and beached. It also had blunt force trauma, and a boat strike was suspected, Gabriele said.

The vessel management program arose from the belief in the late 1970s that excessive boat noise was chasing the whales from the park. In those days, there were fewer than 20 whales in Glacier Bay, and less boat traffic.

Now, three to four dozen whales are in the park on any given summer day.

The vessel management program requires boat operators to attend a 20-minute orientation in which they view a film and talk to a ranger about how to safely navigate around the whales.

Another component of the program is to get boats to slow down: a study found whales were more likely to survive a collision when vessels were going less than 14 knots. Vessel operators also may be required to stay mid-channel because most humpbacks are found close to shore.

Vessel operators are also prohibited from coming within a one-quarter nautical mile of a humpback whale. The park had restrictions in place this summer from May to early October.

The National Park Service put observers aboard almost every cruise ship coming into Glacier Bay this summer to gather information on how close whales come to ships. The data will be used to assess the risk of a whale colliding with a ship.

The National Marine Fisheries Service, which has jurisdiction outside park boundaries, said so far this year there have been five confirmed reports of boats, most of them smaller boats, hitting whales.

Between 1978 and 2006, 62 large whales were struck by boats in Alaska. Forty-six were humpback whales and most were in the southeast, said Aleria Jensen, a fishery biologist and marine mammal stranding coordinator with NMFS.

In 2001, the agency adopted regulations prohibiting boats from coming within 100 yards of a whale and requiring operators to adopt a slow, safe speed. It is up to boat operators to determine what that speed should be.

"I think there is greater awareness in general in the maritime community about the risk," Jensen said.

One whale was found dead outside park waters this summer near Juneau. It had a grotesquely swollen tongue, leading observers to first suspect the whale may have died from a severe infection. A necropsy showed the animal more likely died of blunt force trauma.

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his undated photo provided by the National Parks Service photographed under the authority of a National Marine Fisheries Service Permit No. 945-1776 show two humpback whales swimming by a cruise ship in Glacier Bay National Park and Preserve in Alaska. Visitors to the national park in southeast Alaska saw a record number of humpback whales in Glacier Bay or in waters just outside. (AP Photo/National Marine Fisheries Service )